Digging adjustment for endless type trench excavators



1952 D. F. PRZYBYLSKI 2,584,237

DIGGING ADJUSTMENT FOR ENDLESS TYPE TRENCH EXCAVATORS Filed Sept. 7,1948 10 Sheets-Sheet 1 4 IN VEN TOR.

6&(2/2/ JQ/ rngg 1952 D. F. PRZYBYLSKI 8 DIGGING ADJUSTMENT FOR ENDLESSI TYPE TRENCH EXCAVATORS l0 Sheets-Sheet 3 Filed Sept. 7, 1948 10Sheets-Sheet 5 Feb, ,5, 1952 D. FVPRZYBYLSKI DIGGING ADJUSTMENT FORENDLE TYPE .TRENCH EXCAVATORS Filed Sept. 7. 1948 D. F. PRZYBYLSKIDIGGING ADJUSTMENT FOR ENDLESS Feb. 5, 1952 2,584,287

-TYPE TRENCH EXCAVATORS V =Filed. Sept. 7, 1948 10 Sheets-Sheet 6INVENTOR.

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Feb. 5 l952 D. F. PRZYBYLSKI DIGGING ADJUSTMENT FOR ENDLESS TYPE TRENCHEXCAVATORS .10 Sheets-Sheet '7 Filed Sept. '7 .1948

A .A u W M x H w i m k s L. Q Q 8 M80 F 1952 '0. F. PRZYBYLSKI 4, 8

DIGGING ADJUSTMENT FOR ENDLESS TYPE TRENCH EXCAVATORS Filed Sept. 7,194a 1o Sheets-Sheet 8 III IN VEN TOR.

BY K/ I F 5, 1952 n. F. PRZYBYLSKI 2,584,

DIGGING ADJUSTMENT FOR ENDLESS TYPE TRENCH EXCAVATORS- Filed Sept.7,..1948 1O Sheets-Sheet 9 IN VEN TOR.

Feb. 5, 1952 D. F. PRZYBYLSKI 2,584,287 DIGGING ADJUSTMENT FOR ENDLESSTYPE TRENCH EXCAVATORS Filed Sept. 7, 1948 10 Sheets-Sheet 10 l 2/2 24 gc ,2/5' z/kg 200 221 a w 5!: I 5

Patented Feb. 5, 1952 UNITED STATES PATENT orrlcs DIGGING ADJUSTMENT FORENDLESS TYPE TRENCH EXCAVATORS Daniel F. Przybyls ki, Winona, Minn.Application September '7, 1948, Serial No. 48,121 9 Claims. (01. 37-90)My invention relates to improvements in trench excavators, and, moreparticularly, to such an excavator of the ladder type.

An object of this invention is to provide a self-contained andself-propelled trench excavator;

Another object of this invention is to provide a trench excavator havinga novel grade holder and crumber.

Still another object of this invention is to provide novel ram controlsfor the crumber.

A further object is to provide novel driving connections from an enginefor operating an endless shovel chain having attached shovels.

A further object of this invention is to provide a novel hydraulic liftfor a shovel boom.

Other objects of this invention willbe apparent from the followingdescription and thefaccompanying drawings.

To the above end, generally stated, the invention consists of the noveldevices hereinafter described and defined in the claims.

In the accompanying drawings, which illustrate the invention, likecharacters indicate like parts throughout the several views.

Referring to the drawings: 1 Figs. 1 and 2 are left-hand sideelevational viewed the improved trench excavator showing, respectively,the front end portion and the rear endportion thereof;

Fig; '3 is a fragmentary detail view in plan of thejliydraulic boom liftand associated parts;

Fig. 4 is a detail view partly in side elevation and'partly inlongitudinal vertical section taken on the irregular line 4-4 of Fig. 5;Fig. 5 is a plan view of the parts shown in Fig. 6 is a fragmentarydetail view partly in side elevation and partly in longitudinal verticalsection taken on the line 6-6 of Fig.

Figs. 7, 8 and 9 are fragmentary detail views partly in elevation andpartly in section taken on the lines 1'I, 8-8, and 9-9 respectively ofFig.6;

Fig. 10 is a fragmentary view principally in planwith some partssectioned on the line Ill-4!! of- Fig. 6;

- Fig.- 11 is a plan view of the hydraulic grade holder'beam and theunderlying crumber, on the same scale as Figs. 1 and 2; g

' Figs. 12 and 13 are plan views showing, respectively, the front andthe rear sections of the-shovel boom; 1

- Fig. 14 is a viewin longitudinal central section taken-on the line Il-I4 of Fig. 12,-and further showing on' the same section line theshovel con-, veyor chain guide;

Figs. 15 and 16 are detail views in section taken on the lines |5-l5 and[6-46 of Fig. 14;

. Fig. 17 is a detail view partly in elevation and partly in sectiontaken on the line Il-l'| of Fig. 13;

Fig. 18 is a fragmentary view in side elevation showing the connectedportions of the shovel boom and its head;

Figs. 19 and 20 are detail views partly in end elevation and partly intransverse section taken on the lines l9-l9 and 20-40 of Fig. 18,respectively;

Fig. 21 is a'view partly in end elevation and partly in transversesection taken on the line 2l2l of Fig. 2;

Fig. 22 is a view partly in end elevation and partly in transversesection taken on the line 2222 of Fig. 2;

. Fig. 23 is a side elevational view of the dirt shields and alsoshowing a fragment of the main side frame;

Fig. 24 is a view partly in plan and-partly in section taken on theirregular line 24-24 of Fig. 23; and

Fig. 25 is a perspective view of the winch for adjusting the dirtshields and a fragment of the main side frame to which it is attached.

It may be here stated that Figs. 1, 2 and 11 are all on the same scaleand all of the other figures are on the same scale but on a larger scalethan the first noted scale.

1 The trench'excavator, which is the subject matter of my presentinvention, is a self-containedunit propelled by an internal combustionengine indicated, as an entirety, by the numeral 23 with the exceptionof its shaft 24. This engine 23' is mounted on the front end portion ofa bed 25 forming a part of a novel vehicle which includes two sideframes 26, a rear driven axle 21, a front member 28 and two full tracks29. The rear axle 21 is mounted in an axle housing 3|! having as a partthereof a differential housing 3|. The axle housing 30 extendstransversely under the rear end portion of the bed 25 and is rigidlysecured thereto. The front member '28 connects the side frames 26 to thebed 25 for limited oscillatory movements in vertical planes.

Each full track 29 includes a multiplicity of hingedly connected cleats32 in endless arrangement and each cleat 32 has a cog or tooth 33. Thefull tracks 29 run over driven sprocket wheels 34on the rear axle 21 andidle front sprocket wheels 35 each having a short axle' pneumatic tiresmay be used place of the I tracks.

The rear axle 21 is driven from the engine 33 by the followingconnections, to w-it: a long sectional drive shaft 4|, journaled inbearings 42 cn the bed 25, is driven at its front end from the engineshaft 24 by a sprocket chain 43 that runs over triple sprocket wheels 44and 45 on the engineshaft 2 4; andthey drive shaft 4], respectively. Theconnections also include, in connection with the. drive shaft 4|, fourtransmissions, 4,6,and a flexible coupling 48, between each adjacent.pair. of transmissions 45.. The drive shaft 4| has an oblique rear endextension 45; connected thereto by a universal joint 50 and to a shortshaft:.5.| by a second universal joint 52, and which short shaft forms apart of the differential mechanism in the housing 3|.

On the rear end. portion of the bed 25areupstanding. mainside frames 53made up ofangle bars. Each side frame 53- includes an upright bar 54substantially directly over the-rear axle housing; '30, an oblique bar55 that extends from the top of the bar 54 forward-1yand downwardly tothe bed 25, a short horizontalfbar 5 6 that ex tends rearwardly'from theupper end of the upright bar 54 and an oblique bar 51 that extends fromthe lower end of the uprightbar 54 to the outer end of the horizontalbar 55. The two side frames 53 are rigidly connected at the rearendportions of the horizontal frame bars-:55 by an angle bar 58, and atthe front; end portions of saidbars by-a channel bar 59*.

A si ye r esha t 61 s iqmt a e in beari s 61. on, shor jang belts/6 estd, o e. oblique side frame bars 55 This shovel drive sha t s d v n m hsr e sha t 1' by t following. anima i t wit: a sp ock t... c i runs o e arocketv heel on the, d ive shaft 4|, between the first and 'thesecondtrans missions 4,6,, and asprocket Wheel 65lsecurfedjto a safety clutch55 on a shaft'G'I spaced above the, drive. shaft 4| andjextendingparallel thereto. This shaft 51 is journa led in'bearings 58 onasecondary frame 69. on; the bed 25. On'therear end of the shaft 61 is. abevel pinion 1 that meshes with a bevel gear. H on a. lowercountersliaftflz 'QurnaIed 'in bearings on the side frame bars 55. Asprocket chain 13 runs over a sprocket wheel. 14 on. the lowercountershaft 12 arid a sprocket wheel 15011 the never drive heiiifi Ashovel boom I6 projects rearwardly from h share; d i eshaft a d me n edee e r me S i i gm vemen h s' oom; .6, as shown, is a long H-bar. 11;.the, front end pori p ,1 11 3 1. q nin F -f .5 e e end portion of whichis shown in Fig. 13. The, majorportion of the section of the boom, 15;;shown in Fig. 12, is provided'with top and botome verat 1.8 and l9; respctiv lyr ri dly- 4 flanges of the H-bar 11, see Fig. 16. The flanges ofthe H-bar I1 and the cover plates 18 and 15 form a box-like structurethat extends from the front end of said H-bars rearwardly, see Figs. 12and 14.

The shovel boom 16, on its front end portion, has a V-shaped head 80,the arms 8| of which diverge forwardly and have on their front endstwo-part clamps B2 turnably'mounted on short sleeves 82" ontheshoveldrive shaft and support the boom 15 for vertical swingingmovement. The sleeves 82' form integral parts of the bearings 6|.Thearms 8| are rigidly and interme atelyconnected by a transverse plate83. A cas iiig 84 i rigidly secured to the outer face of thepl'tt 83anolhas on its inner face a central boss 85, that extends through anaperture in said plate, see Figsfl and 5. This boss 85 has a hexagonalrecess in which is rigidly secured a correspondingly formed nut 86. Onthe inner en por ion of the a ms 8| i on w -Pa sleeve 8] in which the.frontend of the H-bai: T1. is slidably mounted. The members of thesleeve it! are channels and the flanges thereof are in oppq si ngrelation andslightly'spaced apart, see 20, 'These members of the sleeve81 are. connected by ,upper. and lower pairs of nut- Lie-b e 81 attendth w n n n holes in lugs 89 on said members The n f 9. b 9- i ri d ycu ed n th bottom plate 1,9,1 at-the transverse center there; of, I fora v purpose which. will. presently appear. e 90, asshown, is a flatplate set edge; vertical plane'and .is downwardly an nea -yams? inclned. sse o f fan 8; ,T brace 98 "extendslbetween the members; of thesleev 87,, at the'r'ear end portion thereof, and hence, it is vnecessary to onset the lower rearmost tie-bolts 88 to afford clearancetherefor by means of ,a pair. of fiatbars 9| and two pairsof ribs a'i,The flat bars 9| extend longitudinally and vertically .dgewise under thelower flanges and are rigidly affixed to said sleeve. and fiat ars. T iqw r eermd t a r f s. 9. depend a sre rajeis. n t e. i z an a i d e' reh r gse Figs, 1,8 in A. long adjusting screw 93 havinga, hexagonal headWWhiC tm be t rn d has h i q d, o gagement with thefnut iifi anditsinner end-in pinge he'.clo sed front'endofthe; H.-bar 1 1. Obviously,by turninglthe screw. 93, the H-barv i1, maybe 'endwise adjustedrelative to th e boom head 80 to afford a take-up fora shovel conveyorchain, as will presently appear.

A heavy endless shovel conveyor sprocket chain-1 5; r ms; r a re r l. 96k red, to the shovelri haft; 6% idw y et en. the; clamps 82-on the boomhead; arms 8| and a d e-sprocke wh e d s! l p o ket s cur d: ba he lonitudinal; d portions of the W el. 911 iour l d mpai of laterally. s ced:side bars 98 rigidly secured to the outer faces; o herbar "an forms t. rar e ext ns oi. Q1 e uter s e f. a h. i e] ar...

at the transverse center thereof, is a reinforcing rib that extendssubstantially the full length of; said sidebar. The ribs 59;, at theirrearends,

are forked and extend; to the longitudinal edges,

the side flanges of the H-bar 11 on the outer faces thereof justrearwardly of the rear end of the top cover plate 18 and supportsaidsprocket wheel above the web of the H-bar 11, see Fig. 2. A guardI02 is secured to the H-bar 11 close to the idle sprocket wheel 91 toprevent sagging of the upper .run of the sprocket chain 95 as it passesonto said sprocket wheel.

A plurality of shovels I03 are secured to certain of the links in theconveyor chain 95 by means of posts I03 spaced equidistantly apart. Thelower run of the conveyor chain 95 moves in a guide I04, in the form'ofan inverted channel, during its upward travel. This guide I04 is rigidlyheld suspended from the H-bar 11 by 1 short upright angle bars I05 withtheir flanges in diverging relation to the longitudinal axis of saidbar. These angle bars I05 are used singly except the foremost one, wherethe sprocket chain 95 leaves the guide I04, which is double with the twoangle bars I05 in opposing relation to form a hollow square structurethat is held by the brace 90, see Figs. 14 and 18. The shovel sprocketchain guide I04 comprises a pair of angle bars I 06 and a web I01connecting the same. It will, of course, be understood that a singlechannel bar may be used in place of the angle bars I06 and web I01. Thepurpose of the guide I04 is that when the machine is digging, pressureon the shovels I03 will cause the same to push upwardly against theguide I04, as a base of resistance, and act as struts for the posts I03and thus prevent backward tilting thereof by digging pressure. Tiltingof the posts I03 would, in turn, tilt the shovels I03 downwardly andthereby cause the same to dig in and prevent a uniform cut for eachshovel I03. This guide I04 also serves the purpose of reinforcing theshovel boom 16 and guides the shovels I03 to make a straight cut.

A grade holder I08 in the form of a stationary beam having a reinforcingtruss I08 overlies the shovel boom 95 in the plane thereof, and isrigidly secured to said boom by means of a front mount or anchor I09 anda rear mount H0. The front mount I09 is a fabricated octagonal structurethat extends transversely of the shovel boom 16. The top of the frontmount I09 is horizontal and there is a gap in the under side thereof.The lower oblique sides of the front mount I09 are rigidly connected bya transverse angle bar III. A short post II2 supports the front mountI09 on the shovel boom 16 and to which boom and the angle bar III saidpost is I rigidly secured. The grade holder I08, at its front endportion, is rigidly secured and anchored to the front mount I09, asindicated at .3, see Fig. 21. The rear mount H is a rectangularfabricated structure that extends transversely of the shovel boom 16 andits bottom member is a large angle bar II4, the end portions of whichextend outwardly of the side members of said mount. A short post IIsupports the mount IIO on the shovel boom 16 and is rigidly secured tothe angle bar H4 and boom 19, see Fig. 22. The grade holder I08 rests onthe top of the rear mount H0 and is rigidly secured thereto, asindicatedat II6. Anchor pins II1, for a purpose 'Fig'JZ. The upper -runoftheshovel chain 95 6 extends through the two mounts I09 and H0. Theshovel boom is operated by a hydraulic lift II9 that includes a longhorizontal cylinder I supported on the angle bar 58 to which it ishinged, as indicated at H9 This cylinder I20 is further supported in asleeve I III forming a part of a casting I2I on the channel bar 59 andsecured thereto by bolts II9. Formed with the'sleeve H9 on each side ofthe cylinder I20 is a bearing I22, to which bearing and the casting I2Ia large directional grooved wheel I23 is journaled. A piston I24 in thecylinder I20'has a piston rod I25 that worksthrough the front end ofsaid cylinder; On the outer end of the piston rod I25 is a bifurcatedbearing I26 to which is journaled a large grooved wheel I21. A pair ofdirectional grooved wheels I28 is journaled in bearings I29 on the frameangle bar 58. The pairof wheels I23 and the wheel I21 are horizontallydisposed and the wheels I28 are vertically disposed. A cable I30, foldedupon itself, extends at its intermediate portion, around the wheel I21and its folded sections are arranged to run around the pairs of wheelsI23 and over the wheels I28 and its end portions are tied to the anchorpins I I1 on the rear mount H0. 'The piston I24 is operated by a fluiddelivered by a pump I3I to the cylinder I20 from a supply tank I32through a tube "I33 in which is interposed a control lever I3I. Thispump I3! is driven by the sprocket chain 63.

A crumber I34 including a boom I34 extends rearwardly from the rearmount I I0 between the grade holder boom I08 and the shovel boom 16.This crumber boom I34 includes a pair of laterally spaced square tubularbeams I35 pivoted at their front end portions to and between pairs ofbearing lugs I36 on the top member of the rear mount [I0 for verticalswinging movement. The two crumber beams I35 are rigidly crossconnectedat their fear or free end portions by an angle bar I31. The crumber boomI34 fur ther includes a reinforcing truss I38. Each crumber beam I35 hason its free end a downturned extension I39 that is perpendicularthereto.

The crumber I34 further incluudes a transverse scraper blade I40, thewidth of which corresponds to the widthof the trench dug by the shovelsI03. The shape of the scraper blade I40 conforms to the arcof a circlehaving its center substantially at the axis of the idle sprocket wheel91 on the shovel boom 19. This scraper blade I40 is in frontof thecrumber beam extension I39, is'rigidly secured at its upper'edge to thecrumber beams I35 and said crumber beam extensions I39 afford a base ofresistance'for the scraper blade I40 at its lower portion. The purposeof the scraper blade I40 is to smooth the bottom'and sides of the trenchand push surplus dirt to the shovels I03.

A pair of rearwardly projecting side plates I4I, between which thecrumber beam extensions I39 extend, is rigidly secured to saidextensions and the scraper blade I40, as indicated at I42. On the backof the scraper blade I40 is a pair of extension plates I43, to increasethe width of said scraper blade'when shovels of a greater width are usedin place of the shovels I03. These scraper blade extension plates I43are adjustably secured to the scraper blade I49 by nut: equipped boltsI44 which extend through holes in said scraper blade and horizontalslots I45 in its extension plates I43, see Figs. 6 and 9. T

The crumber I34 is helddown to its work by bearing plat s I6 to inreaseheng le b etyyee x Sides of the trgnq frgm'llli g in thwmie d ii shfBPA' h'e, b 61 16 W1 12; ed o o g A 4 a 9 from the shaft '61 by 2, sp gke t pam I18 tpjgf; WRQQVFE $.1 39 whs "9.0 h ear end conveyor H4. T purheld f rom tur n while thjsciapiibris l3] alie Sleeve andfbearii g i Qna i q 9?? h and nut I96. During the upward travel of the shovels I03around the driven sprocket wheel 96,

-the inner surfaces of said shovels pass just out that may adhere to oneof the shovels I03, or

removing a rock or other obstruction therefrom, one or both of theshearing pins I89 will be severed and allow the engaged scraper bar orbars to move with the respective shovel I03. Movement of one Or both ofthe scraper bars I81 with a shovel I03 will turn one or both of theshafts I90 and thus cause the crank arm or arms I90 to compress one orboth of the long springs I91 and the progressive increase in the tensionof one Or both of said springs will progressively increase theresistance of the scraper bar or bars I87 to remove an obstruction froma shovel I03. The eccentric pivotal movement of the scraper bars I81,relative to theaxis of the shaft 60 about which the shovels I03 arebeingmoved by an engaged obstruction o a shovel I03, will, during extremerearward movement of said scraper bar or bars, cause the said scraperbars to move shovels I03.

when the machine is digging, the hydraulic lift H9 is free, the crumberslide I51 and its shoe l58 are resting on the bottom of the trench, the

grade holder I 08 at its rear end is supported from the crumber by theram I46, and said grade holder supports the shovel boom I6, to which itis rigidly secured by the mounts I09 and H with its shovels I03 indigging position. To permit the shovel boom 16 to dig deeper, it is onlynecessary to release the fluid in the ram cylinder '14? and the weight.of said boom will move the same down.

It will thus be seen that the hydraulic grade holder I08 is used to aidthe operator in obtaining a smooth and more accurate grade line inthe'bottom of the trench. The shoe I58 is used to impart straight linemovement to the shovels I 03.

The shovel boom I6 is lifted out of a trench by means of the hydrauliclift I I9 and held thereby raised above the ground together with thegrade holder I08 when the machine is travelling on the road or beingreset, etc. The rear end portion of the crumber boom I35 is connected tothe grade holder I08 by means of a chain I99. This chain I 99, when themachine is operating, is slack. so as not to interfere with theoperation of the ram I46 and the relative adjustments of the crumber andthe grade holder I08. When the shovel boom I6 and the grade holder I08are being lifted and held above the ground by the end portion overlapsan inner ear-202 on a plate 203 and is pivoted thereto, as indicated at204. The front end portions of the horizontal flanges of the angle barsI and 205 are cut away to clear the ears 202 and 201 during theraising'or lowering of the dirt shields I84. The plate 203 is rigidlyaifixed to the rear end of the bed and supports the dirt shield forvertical swinging movement.

The horizontal brace 205 is secured at one of its end portions to theangle bar20| at its rear end portion by a pair of bolts 206, see Fig.24. The forward end portion of the vertical flange of the angle bar 205overlaps an outer ear 201 on the car 20'! and one of apair ofhorizontally spaced holes 209 in said flange. The two ears 202 and 201on the plate 203 are laterally spaced aconsiderable distance apart andhold the brace 205 obliquely to the dirt shield I84. By shifting thebolt 208 from one of the holes 209 to the other, the operative length ofthe brace 205 may be varied, at will. This adjustment of each brace 205spaces the dirt shields I 84 at their sions of the dirt shields I84.Each side plate 2 hydraulic lift I I9, the chain I99 holds the crumbersuspended from said grade holder.

Referring now in detail to the dirt shields I84, each of which is madeof a single sheet of metal on .the winch 2I5.

has an upwardly and outwardly inclined dirtdefiecting top member 2I2 andan upwardly and rearwardly inclined dirt-deflecting top section 2I3.These dirt-deflecting sections 2I2 and 2I-3 direct dirt precipitatedfrom the shovels I03 either back into the trench or onto thecrossconveyor I14. The side plates2II are connected at their upper frontend portions by a cross-tie angle bar 2I I. Secured to each dirt shieldI84 is a forwardly projecting extension 2I4 that closes, the gap betweenthe dirt shield I84 and the respective side plate 2| I.

The dirt shields I84 are simultaneously raised or lowered by means of awinch 2I5 and the following connections, to wit: A rock shaft 2I 6journaled inbearings 2II on the angle bar 58 has on its right-hand endan arm 2 I8 and On its left-hand end is a lever 2I9 having a short arm220 that is a duplicate of the arm'2I8 and a long arm 22I. A pair ofcables 222 is attached at one of their ends toeyes 223 on the outer endportions of the angle bars 20! and attached at their other ends to thearms 2I8 and 220. A third cable 224'is attached at one of itsends to thelong arm 22I and its other end portion is wound The winch 2I5 is mountedon the left-hand angle bar 51 and is provided with a dog 225 and aco-operating ratchet wheel 226 to prevent the winch 2I5 from turning bythe pull of the dirt shields I84 thereon, and thus unwind the cable 224therefrom. Obviously, by operating the winch 2I5, the dirt shields I84may be raised or lowered, at will.

its front vertical edge portion, by an 'angle bar The'purpose of thedirt shields I84 is to insure reinforced at its entire marginal portion,except j clean shoulders at the top of a trench being dug.

-and,'theside plates'2I I, and which dirt shields and side plates willhold the dirt from falling off said shovels.

The drawings illustrate a commercial form of the trench excavator. butit will be understood that thesame is capable efiagiarge'rangeefmodification 'withi'n Y the spirit of the invention-herein disclosedand'claimed.

*WhatI claim is: 1. In a machine of the 'class' 'desc'ribed, :en

engine-propelled vehicle, l a rea rwardly projecting shovel boompivotedat its J front end to the vehicle to swing vertically-2 hydrauliclift 'for raising or lowering the shovelboom,' -shovels mounted onthe'shovelboom totravel an end- 'less course, Zmeans for operating"the'sho'vels 'from the engine, front and rear-mounts on the shovelboom, a-gradeholder beam overlying-the shovel boom and 'the I mounts,said '--grade holder beam being rigidly secured to the -moiints at itsfront end portion, acrumberineluding a boom extending longitudinallybetween the shovel boom and the grade'holderbeam andpivoted: at

its from end portion to the *rear mount, said crumb'er boom having adownturnedrear-"extensionyas'craper blade in 'fro'nt of the crumber boomextension, a slide pivotedto the-lower edge portion of the scraperblade,ram controlsbonnecting the grade hol d'er beam "and the crumber and theslide and the-'crumber.

2. In an excavator 'for cutting a trench having a smooth bottom on anaccurategrade line, avehicleprovided with a rearwardly 'proj e'ctingshovel boom horizontally pivoted at its front end in respecttdthevehicle'whereby the "rear endof the "shovel boom may be swungvertically, shovels mounted on the shovel boom to travel'an endlesscourse, power means for operating-the shovels, '-a grade l'lolder beamoverlying the shovel boomand immovably-se'cu'red to said shovei'boomacrumber :boom overlying the shovel boom and positioned betweensaid'shov'el boomandthe grade beam, the crumber boom projectinre'arwar'dly from the vehiclean'd beingh'orizontallypivotally supportedat its frontend bythe shovel boom Whereby its'rear'end ma'y be swunvert'ically, the'rear end of the crumber boom being supported upon'asli'de disposed on anda'da'pte'd to slide over the bottom of the trench'a scraper blade "carried by the rear end of the 'crumb'er boom and"disposed immediately behind the shovels in their -movement through therear end of their "course or the number boom and the grade beam'forsupp'or-ting'the' grade beam 'and thereby supporting 5 the rear "endof the 'shovelboom in' respeet to the bottom of the trench.

3. Acons'truction asdefi'nedin'claim 2 wherein, the connection betweenthe Erear endrot the -c'ru'mber boomand the'grade beam islin the form ofa longitudinallyextensibleand contractable member, and means forextendingsandz'contra'ct- 'ing said member for vertically selectively"adjusting the rear end of 'the shovel boom in resp'ectrto the bottom ofthe trench.

*4."A'co'nstruction asdefined in 'claim 2 wl1erein,

' the siipporting engagement' between thet=rear end of the crumbe'r boomand the slideiisatithe forward-{end of thesli'de and is in the'formtofahoriz'on'tall'y disposed piVOtJmeans interoonnectingthe rear end of theslide withrthe crumber boom ata -point above itspivotal connection withthefslide for preventing 'pivotalc movement of the '1 slidein re'spe'ct"to the 'crumber .b oom, saidimeans i being 3 in the form lof alongitudinally.iextensible "and *contraetable device; and means forselectively ex- 12 tlidifi'g'"oriijofttidiitirig -sarYd di iCBIGrSelectively raisi ng and iowermgtne front ex id of the slide.

' 1 5. A construction:asnefinedin tiaim z wherem, the connection betweenthe 7 rear end 03 the 'x'zrumber 'boom and the igr ade beain in the'form of a hydraulicram, means forselectively extend- .ing' andietvactingthe ram for r'ai'si'mg and lowering therear'end of the -grade--beamforselectively supportin the rear end of the shovel boom-in respe'e'tto' the bottomo'f the trench, the connection -btween' the 'rear end ortlie crumb'er boom and the" slide being in -the form o'f a horiiontalpivot p'ositioned at the front end (iftli'e slidm-ahydraulicallyoperate'd ram interconnecting the i ear end of the slidewitntheerumberboomata point :above the connection of the rumber 'boo'mwith the slide, andmeans to "'seleo'tively extend and re- 'tra'ct lsaidram-to: selectively r ai'se -and' lo'wei the 6. A construction 'aisde'fiiiedin cla'im zwhfin, power means is provid'e'd on thevehicI-eandconnected t'olthe shoV1 bOOm foriaising it together with i theinterconnected :crumber b'oom, g'fade beami gnd slidecfron'i' -the'tren'ch andIoweriiigsaid f traveL- a'nd a connection between the'rearend of e1ements -int'o the tr'ench,' and means interconnecting' the"grade be'am and cromber boo'm' and operative only when-the parts areraised from tlie trench for supporting th'e crumb'er booin and-itsattached-slide fromthegrade beam.

"7. A cons'truotion' as-de'fined inblaim 2 wherein, a. pair of spa'ced:apart'u'pwardly extending mounts are rigidly secured to the shovel boom,the g'fade holder beam ioverlyin'g "ana h'av ing rigid inimovable.connection flwith ssaid mounts, and the i'cruniber' bo'om h'aving lit's pivotal support'o'n one ofsai'd mounts.

'8. A construction as defined in claim- 2 'v'vherein, "a pair'of mountsare rigidly securedto the-shovel I boom and extend upwa'rdly therefrom'in spac'd relationshineth'e'grade -holder beambverlying and beingrigidly immovabl'ysecured to- 'saidflnounts,

- rear end oflthecrumber boom.

-DAN IEL PRZYBYLSKI.

REFERENGES CITED V The followingreferences are of record inth'e file ofthis patent:

- -UNITED STAT-ES PATENTS

